/**
 * Copyright (c) 2022 aoshiguchen
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package fun.asgc.neutrino.core.aop.support;

import fun.asgc.neutrino.core.aop.Invocation;
import fun.asgc.neutrino.core.aop.interceptor.Interceptor;
import fun.asgc.neutrino.core.util.LockUtil;

import java.lang.reflect.Method;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 单例拦截器
 * @author: aoshiguchen
 * @date: 2022/7/8
 */
public class SingletonInterceptor implements Interceptor {
	private static final Map<Method, Object> cache = new ConcurrentHashMap<>();

	@Override
	public void intercept(Invocation inv) throws Exception {
		LockUtil.doubleCheckProcess(
			() -> !cache.containsKey(inv.getTargetMethod()),
			inv.getTargetMethod(),
			() -> {
				inv.invoke();
				cache.put(inv.getTargetMethod(), inv.getReturnValue());
			}
		);
		inv.setReturnValue(cache.get(inv.getTargetMethod()));
	}

}
